#define _CRT_SECURE_NO_WARNINGS 1
#include"Stack.h"
void STInit(ST* ps)
{
	assert(ps);
	ps->a = NULL;
	ps->top = 0;
	ps->capacity = 0;
}

void STDestroy(ST* ps)
{
	assert(ps);
	free(ps->a);
	ps->a = NULL;
	ps->top = ps->capacity = 0;
}

void STPush(ST* ps, STDataType x)
{
	assert(ps);
	if (ps->top == ps->capacity)
	{
		int newcapacity = ps->capacity == 0 ? 4 : ps->capacity * 2;
		STDataType* new = (STDataType*)realloc(ps->a, sizeof(STDataType) * newcapacity);
		if (new == NULL)
		{
			perror("realloc fail!");
			return;
		}
		ps->capacity = newcapacity;
		ps->a = new;
	}
	ps->a[ps->top] = x;
	ps->top++;

}

void STPop(ST* ps)
{
	assert(ps);
	assert(ps->a);
	ps->top--;
}

STDataType STTop(ST* ps)
{
	assert(ps);
	assert(!STEmpty(ps));

	return ps->a[ps->top - 1];
}

int STSize(ST* ps)
{
	assert(ps);

	return ps->top;
}

bool STEmpty(ST* ps)
{
	assert(ps);

	return ps->top == 0;
}